Common Core Standards
Grade 2
Language L.2.1.F
Produce, expand, and rearrange complete simple and compound sentences (e.g., The boy watched the movie; The little boy watched the movie; The action movie was watched by the little boy).
Independent clauses: it's a love-hate relationship, even for adults. Keep it simple, but make sure second graders understand that the independent clause is the basis of both simple and compound sentences.